You can cram yourself with food, or cram your books onto a shelf that's not quite big enough to hold them. A writer might cram one book with dozens of characters, or you could cram homemade pancakes with blueberries. Another way to cram is to study for a test all in one session: "I haven't studied at all yet — I'll have to stay up tonight and cram." The Old English root, crammian, means "stuff something into something else."